Laminated shim



20, 1934-. A JOHNSON 1,951,730

LAMINATED SHIN Original Filed May 27, 1929 J Ila IN VEN TOR.

LLOYD A. c/Qff/VjO/V BY QM k TORNEY Patented Mar. 20, 1934 PATENT OFFICE LAMINATED SHIM Lloyd A. Johnson, Hillsbcrough, Calif.

4 Claims.

The present invention relates to improvements in shims and is a division of my former applica tion Serial No. 366,478, iiled May 27, 1929, now U. S. Patent 1,808,942, April 14, 1931. As is well known in the art, shims are used to provide for taking up wear in bearings, to adjust the spacing of gears or housings, and in a variety of other applications. A shim usually comprises a plurality of thin lamina held together or secured to a body plate in such a manner that the laminae may be readily detached, one at a time, or, as desired, so as to reduce the thickness of the shim by a predetermined amount.

A more recent development in the art is the babbitt-tippecl shim for use with bearings provided with forced feed lubrication. The ordinary shim does not contact with the shaft in the bearings but is spaced slightly therefrom so as not to scrape the shaft. This spacing, however, leaves a channel through which oil may escape and in a pressure lubricating system it constitutes a serious leak which lowers the pressure of the system. The babbitt-tipped shim overcomes this defect because it is provided, on its inner edge, with a lug or facing of Babbitt or other bearing material which closes the channel above referred to and maintains the pressure in the oiling system. In some cases, the channel is not entirely filled up by the lug, but is merely closed at each end by short lugs of bearing metal secured to the shim, leaving a pocket for oil between the lugs.

My invention has for an object to provide an improved shim either of the plain or of the babbitt-tipped type.

Shim lamina are made of very thin metal (usually brass) and the metal is comparatively expensive because of the labor involved in rolling it down to the requisite thinness and to accurate gage. Under ordinary conditions, it is not necessary to make the entire shim of thin lamina, nor is it desirable to use the thin brass for this purpose without a substantial backing, because the metal is comparatively soft. It is customary, therefore, to make shims with a heavy body plate, or, in some cases, with. several plates of substantial cross-section, and then to apply a limited number of thin laminae to these plates, joining the whole by means of solder or other adhesive or cementing material. I-Ieretofore, it has been found necessary to use brass for the body plate of the shim. There are two reasons for this choice of metal: (1) The brass will not corrode when subjected to moisture; (2) it lends itself readily to soldering. With the object of reducing the cost of shims as much as possible, efforts have been made to use a less expensive metal for the body plate of the shim. A desirable metal for this purpose is steel or iron, steel being preferable because of its hardness, but the chief drawbacks to steel are the readiness with which it rusts and the difiiculty with which it takes solder. When the lamina are soldered to a steel body plate the latter must be treated with acid flux. This acid starts corrosion which gradually creeps over the entire surface of the plate. The corrosion acts not only to separate the lamina from the plate, but also has a tendency to increase the thickness of the shim. For these reasons, a body plate of ferrous metal has heretofore been considered unsuitable for use in a shim.

However, I have found that a shim may be made economically with the use of steel or other f rrous metal or alloy, as the base plate, provided the steel is plated or coated with a material which will not only protect it against rust, but will also provide a good bond for the solder or other adhesive used. In my copending application, Ser. No. 366,478, filed May 27, 1929, I describe a process of making such a shim. The present application is a division of said copending application and relates particularly to the shim structure. Thus it is a specific object of the present invention to provide a shim in which a plurality of laminae is secured to a base plate of ferrous metal provided with a protective coating. Various metals may be employed for plating the steel, such for instance as copper, nickel, etc. I have found that cadmium makes a particularly satisfactory coating material, because it maintains a good appearance and will not tarnish, because it protects the iron against rust, and because it provides an excellent bond for solder.

Another object of the invention is to provide a shim of this type in which the bearing edge of the shim is fitted with a facing of Babbitt or other bearing material.

Other objects and advantages of my invention Fig. 2 is a view in cross-section, the section being taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in perspective of the body plate used in my shims, with a part of the Babbitt facing thereon; and

Fig. 4 is a view in perspective of a number of ice laminae ready to be applied to the body plate shown in Fig. 3.

The particular shim illustrated in the accompanying drawing is one in which the body plate is located in the middle of the shim with laminae on opposite faces thereof. However, the particular form of the shim is immaterial and the shim can just as well be made of entirely different shape and with a different arrangement of parts, provided it has at least one body plate. In the drawing, the numeral 10 is used to indicate the body plate of a shim. This plate is provided with a central opening 11 to serve either as a bolt hole or an opening through which a centering stud may pass. The forward edge of the plate 10 is of undulatory form with orifices 13 pass ng through the plate within each undulation. The plate is stamped out of a steel sheet and hence the edges of the plate are rough at the edge. When steel is cut out by means of dies it is not severed smoothly, but breaks. The broken edge is granular and provides an excellent surface to which a plating will adhere. The orifices 13 will also have similar roughened surfaces with which the plating may knit very closely.

After the plate has been out out and perforated, as shown, it is subjected to a plating treatment. The plating may be deposited mechanically or electrochemically according to the metal used. As explained above, I prefer to use cadmium although other plating metals can also be used. The cadmium plated body plate is proof against rust and owing to the broken surfaces above referred to there will be very close adherence between the cadmium and the steel along the edges of the plate and particularly in the orifices 13. Cadmium is known to provide a very good bonding surface for solder, Babbitt, and other bearing metals.

. The plate 10 is now placed in a suitable mold and a facing of babbitt 14 is cast thereon. (In the use of the word babbitt I do not confine myself to the particular alloy originally known as Babbitt metal, but also mean to include other bearing alloys which are usually loosely termed Babbitt metals). The facing 14. is applied to the forward edge of the plate 10 and is also carried around the ends of the plate, as indicated at 15. The facing 14 not only fits over the edge of the plate 10 but also enters the perforations 13, and because of the afiinity of cadmium for the babbitt, there is not only a mechanical union of the facing with the plate 10, due to the interlocking of the babbitt with the orifices 13, but there is also a metallurgical union so that the facing 14 is held very securely to the plate 10.

The facing 14 is made of a thickness equal to that of a finished shim; in other words, it stands above and below the plate 10 sufficiently to lie flush with the laminae which are to be applied to the plate 10. The laminae 16 are cut to the form shown in Fig. 4, with a central opening 17 adapted substantially to register with the opening 11, and with offsets 18 adapted to receive the end portions 15 of the babbitt facing. A set of lamina is applied to the upper face of the shim and another set to the lower face thereof, and then the laminae are secured to the body plate by means of solder applied to each end, as indicated at 19, and also to the rear edge of the shim, as indicated at 20. This completes the manufacture of the shim.

It will be observed that the laminae are not in any way secured directly to the facing 14 but are connected thereto indirectly by means of the solder 19 and 20 which attaches them to the body plate 10. Because the body plate is cadmium coated the soldering may be very readily effected, and there will be very close adhesion between the laminae and body plate. It will be understood, of course, that the soldering not only holds the lamina to the plate 10, but also holds each lamina to the adjacent laminae. The fac ing 14 may be cast upon the plate 10 after the laminae 19 have been secured to the plate. I have found in practice that the Babbitt or bearing metal, when thus cast on the plate, will not adhere to the edges of the laminae.

While I have referred to the use of solder for connecting the shims, obviously other adhesive means could also be employed, such as lacquer, cement, or the like, and the adhesive may be applied between the lamina instead of at the edge of the shim. Also, while I have referred specifically to the use of cadmium coating, my invention is not limited to the use of this material but is also applicable to other coating materials. Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. A laminated shim comprising a body plate of steel coated with cadmium, and a plurality of soft cuprous metal laminae lying upon the plate and detachably secured thereto with solder.

2. A laminated shim comprising a body plate of steel coated with cadmium, and a plurality of brass lamina lying upon the plate and secured thereto with solder applied to the edges of the laminae and the plate.

3. A laminated shim comprising a body plate of steel plated with cadmium, the plate having orifices adjacent one edge thereof, a lug of bearing metal cast upon the plate at said edge and penetrating said orifices, and a plurality of brass laminae lying upon the plate with their edges abutting the lug, the lamina being secured to the plate with solder applied to the edges of the plate and the laminae.

4. A shim comprising a plate of steel plated with cadmium, and a lug of bearing metal cast upon one edge of the plate, the plate being formed with recesses in which said lug enters.

LLOYD A. JOHNSON. 

